The primary objective of this proposal is to identify human-mouse conserved noncoding sequences and to experimentally determine the role these elements play in the transcriptional regulation of human genes using YAC transgenic mice. These studies are based on the investigator's previous work characterizing the megabase region on human chromosome 5q31 containing the Interleukin Growth Factor Cluster. Sixteen new genes, as well as 7 previously known genes, were computationally identified and the expression patterns of these genes were determined by a variety of biological approaches. The analysis also demonstrated that the nature and order of the genes in this region on human 5q31 are conserved on the long arm of mouse chromosome 11. In the studies proposed here, the sequence of a 150 kb gene dense region on human chromosome 5q31 will be compared with the syntenic region on mouse chromosome 11 to identify conserved noncoding regulatory elements. Detailed expression patterns of the human genes in this region, which include two interleukins, will be determined by analyzing YAC transgenic mice harboring these human 5q31 DNA sequences. The human-mouse conserved noncoding sequences identified in this study will be functionally characterized to determine if they are regulatory elements by comparing the expression patterns of the transgenes contained on unaltered human 5q31 YACs versus a series of modified 5q31 YACs in which conserved noncoding sequences have been deleted. The identification and functional analysis of conserved human-mouse regulatory sequences in this study may deepen our understanding of transcriptional regulation as well as assist in the computational annotation of other biologically important noncoding sequences in the human and mouse genomes.